Island



W. H. JAY.

SCREW PROPELLER.

No. 528,253. Patented Oct. 30, 1894..

.I t I UNITED STATES PATENT OFFICE.-

WILLIAM H. JAY, OF PROVIDENCE, RHODE ISLAND.

SCREW-PROPELLER.

SPECIFICATION forming part of Letters Patent No; 528,253, dated October 30, 1 894.

Application filed December 13,1 8 92- Serial No. 455.032- (No model.)

T0 at whom it may concern.-

Be it known that I, WILLIAM H. JAY, a citizen of the United States, residing at Providence, in the county of Providence and State of Rhode Island, have invented certain new and useful Improvements in Screw-Propellers; and I do hereby declare the following to be a full, clear, and exact description of the lnvention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters of reference marked thereon, which form a part of this specification.

My invention has relation to screw-propellers, butniore particularly to a novel construction of the blades or wings. Usually heretofore, so far as I am aware, screws of this character have been provided with blades having the length of the forward or entering side or edge substantially the same as the rear or discharging side. Moreover, such former screws have been practically alike as regards the form of the two radial edges of the blades. By reason of such construction the blade in working enters the water at its full leverage and pressure, thereby subjecting the shaft and motive power to a continuous series of shocks or jars which act not only to shorten the life of the machinery but at the same time produce a disagreeable sensation and noise.

The object I have in view is to overcome the defects or disadvantages just referred to. To that end myinvention consists, essentially, of a screw-propeller having the entering edge and a small area of each blade formed with a slightly greater inclination or pitch than the major portion of the'blade while the rear or discharging edge is reversely bent or curved. The outer peripheral edge of the blade is. nonconcentric with the shaft, its greatest radius being at the rear edge, and-its greatest width near the hub of the screw. By means ofthis construction and arrangement the blades are adapted to enter the water easier; the gradually increasing area of the blade causing it to cut through the water with less slip, and consequently greater efficiency; the curved portion of the rear edge of the blade at the same time operating to prevent a too free release of the impinging water from the workform any part of my present invention, as thev latter resides solely in the novel construction of the blade itself.

In the drawings A indicates a two-bladed screw-propeller provided with my improvement. The hub portion is designated by h, and aindicates the blades. The blades as drawn are formed integral with the hub, but they may be made independently of it and secured thereto in any well known manner.

The position or location of the. blades with reference to the hub is such that they stand at an oblique angle of about forty-five degrees (see Fig. 4), although the angle may be changed to suit varying conditions. The forward or entering portion 12 of the blade a, is

bent inboard, or toward the vessel,as clearly shown in Fig. 4, thereby forming with the major portion of the working area ct, if continued, an acute anglem, as indicated by the broken line in said figure. When thus bent or formed it will be seen that the blade will present a working surface having an included angle exceeding one hundred and eighty degrees, as indicated by the dotted curved line 6, in the horizontal sectional view, Fig. 4. The part a of the working area forms asubstantially plane or fiat surface arranged obliquely with thehub. The rear or discharge edge 0 of the blade is bent in a reverse direction or toward the shaft, as shown and as clearly represented in Fig. 4. The path described by the outer peripheral edge 19 is not a true circlen (see dottedlines Fig. 2) because I prefer to so make said edge that it is bounded or limited by radii having varying lengths. By this arrangement the power exerted in propelling the vessel against the resistance or pressure of the water is more gradually utilized. At the same time the bent portion In screw-propellers of comparatively small diameter I prefer to employ two blades, but larger screws may have three or more.

I claim as new and desire to secure by and having a plurality of bent blades (1. se-

United States Letters Patent- 1. A screw-propeller blade consisting essentially of a forward 01' leading portion 11 bent inboard and a main portion a arranged at an angle therewith exceeding one hundred and eighty degrees, whereby the said leading portion of the blade has a coarser pitch than the main portion, substantially as described.

2. A screw-propeller blade having its forward portion bent inboard toform an obtuse angle with the plane of the major portion of the blade, and having its rear or releasing portion reversely bent'toward the shaft, substantially as hereinbefore described and for the purpose set forth.

3. A screw-propeller blade having its outer :hereinbefore described.

4. The screw-propeller, substantially as hereinbefore described, consisting of a hub portion. adapted to be fixed to a driving-shaft,

cured to or integral with said hub; each of said blades having a forward or leading portion I) bent inboard anda main portion a arranged at an angle therewithexceeding one hundred and eighty degrees, and having the rear or releasing portion 0 of said main part bent reversely towardthe shaft, whereby the said leading portion of the blade has a coarser pitch than the main portion.

In testimony whereof Ihave aifixed my signature in presence of two witnesses.

WILLIAM H. J AY.

Witnesses:

Gno. H. REMINGTON,

IDA M. WARREN. 

